Add `i8042.exist` to override ACPI flags

Cargo.lock

@@ -165,6 +165,16 @@ dependencies = [
  "spin",
 ]
 
+[[package]]
+name = "aster-cmdline"
+version = "0.1.0"
+dependencies = [
+ "component",
+ "log",
+ "ostd",
+ "spin",
+]
+
 [[package]]
 name = "aster-console"
 version = "0.1.0"
@@ -192,6 +202,7 @@ dependencies = [
 name = "aster-i8042"
 version = "0.1.0"
 dependencies = [
+ "aster-cmdline",
  "aster-input",
  "bitflags 2.9.1",
  "component",
@@ -263,6 +274,7 @@ dependencies = [
  "align_ext",
  "aster-bigtcp",
  "aster-block",
+ "aster-cmdline",
  "aster-console",
  "aster-framebuffer",
  "aster-i8042",

Cargo.toml

@@ -14,6 +14,7 @@ members = [
     "ostd/libs/ostd-test",
     "kernel",
     "kernel/comps/block",
+    "kernel/comps/cmdline",
     "kernel/comps/console",
     "kernel/comps/framebuffer",
     "kernel/comps/input",

Components.toml

@@ -14,6 +14,7 @@ mlsdisk = { name = "aster-mlsdisk" }
 systree = { name = "aster-systree" }
 i8042 = { name = "aster-i8042" }
 pci = { name = "aster-pci" }
+cmdline = { name = "aster-cmdline" }
 
 [whitelist]
 [whitelist.nix.main]

Makefile

@@ -224,6 +224,7 @@ OSDK_CRATES := \
 	ostd/libs/linux-bzimage/setup \
 	kernel \
 	kernel/comps/block \
+	kernel/comps/cmdline \
 	kernel/comps/console \
 	kernel/comps/framebuffer \
 	kernel/comps/input \

kernel/Cargo.toml

@@ -10,6 +10,7 @@ align_ext = { path = "../ostd/libs/align_ext" }
 aster-input = { path = "comps/input" }
 aster-block = { path = "comps/block" }
 aster-network = { path = "comps/network" }
+aster-cmdline = { path = "comps/cmdline" }
 aster-console = { path = "comps/console" }
 aster-framebuffer = { path = "comps/framebuffer" }
 aster-softirq = { path = "comps/softirq" }

kernel/comps/cmdline/Cargo.toml

@@ -0,0 +1,15 @@
+[package]
+name = "aster-cmdline"
+version = "0.1.0"
+edition = "2021"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]
+component = { path = "../../libs/comp-sys/component" }
+ostd = { path = "../../../ostd" }
+log = "0.4"
+spin = "0.9.4"
+
+[lints]
+workspace = true

kernel/comps/cmdline/src/lib.rs

@@ -1,7 +1,5 @@
 // SPDX-License-Identifier: MPL-2.0
 
-#![expect(unused_variables)]
-
 //! The module to parse kernel command-line arguments.
 //!
 //! The format of the Asterinas command line string conforms
@@ -9,6 +7,10 @@
 //!
 //! <https://www.kernel.org/doc/html/v6.4/admin-guide/kernel-parameters.html>
 //!
+#![no_std]
+#![deny(unsafe_code)]
+
+extern crate alloc;
 
 use alloc::{
     collections::BTreeMap,
@@ -18,7 +20,7 @@ use alloc::{
     vec::Vec,
 };
 
-use ostd::boot::boot_info;
+use component::{init_component, ComponentInitError};
 use spin::Once;
 
 #[derive(PartialEq, Debug)]
@@ -47,13 +49,6 @@ pub struct KCmdlineArg {
 
 // Define get APIs.
 impl KCmdlineArg {
-    /// Gets the singleton instance of `KCmdlineArg`.
-    pub fn singleton() -> &'static KCmdlineArg {
-        static INSTANCE: Once<KCmdlineArg> = Once::new();
-
-        INSTANCE.call_once(|| KCmdlineArg::from(boot_info().kernel_cmdline.as_str()))
-    }
-
     /// Gets the path of the init process.
     pub fn get_initproc_path(&self) -> Option<&str> {
         self.initproc.path.as_deref()
@@ -75,7 +70,6 @@ impl KCmdlineArg {
     }
 
     /// Gets the argument vector of a kernel module.
-    #[expect(dead_code)]
     pub fn get_module_args(&self, module: &str) -> Option<&Vec<ModuleArg>> {
         self.module_args.get(module)
     }
@@ -177,7 +171,7 @@ impl From<&str> for KCmdlineArg {
                 // The option has a value.
                 match option {
                     "init" => {
-                        if let Some(v) = &result.initproc.path {
+                        if result.initproc.path.is_some() {
                             panic!("[KCmdline] Init process specified twice");
                         }
                         result.initproc.path = Some(value.to_string());
@@ -205,3 +199,13 @@ impl From<&str> for KCmdlineArg {
         result
     }
 }
+
+/// The [`KCmdlineArg`] singleton.
+pub static KCMDLINE: Once<KCmdlineArg> = Once::new();
+
+#[init_component]
+fn init() -> Result<(), ComponentInitError> {
+    KCMDLINE.call_once(|| KCmdlineArg::from(ostd::boot::boot_info().kernel_cmdline.as_str()));
+
+    Ok(())
+}

kernel/comps/i8042/Cargo.toml

@@ -12,6 +12,7 @@ bitflags = "2.5"
 log = "0.4"
 spin = "0.9.4"
 aster-input = { path = "../input" }
+aster-cmdline = { path = "../cmdline" }
 
 [lints]
 workspace = true

kernel/comps/i8042/src/controller.rs

@@ -5,6 +5,7 @@
 //! Reference: <https://wiki.osdev.org/I8042_PS/2_Controller>
 //!
 
+use aster_cmdline::{ModuleArg, KCMDLINE};
 use bitflags::bitflags;
 use ostd::{
     arch::{device::io_port::ReadWriteAccess, kernel::ACPI_INFO},
@@ -129,15 +130,32 @@ impl I8042Controller {
         const DATA_PORT_ADDR: u16 = 0x60;
         const STATUS_OR_COMMAND_PORT_ADDR: u16 = 0x64;
 
-        if ACPI_INFO
-            .get()
-            .unwrap()
-            .boot_flags
-            .is_some_and(|flags| !flags.motherboard_implements_8042())
-        {
+        if !Self::is_present_acpi() {
             // The PS/2 controller does not exist. See:
             // <https://uefi.org/specs/ACPI/6.5/05_ACPI_Software_Programming_Model.html#ia-pc-boot-architecture-flags>.
-            return Err(I8042ControllerError::NotPresent);
+            //
+            // However, it may actually be present and enumerable from other sources, such as PnP
+            // devices. See:
+            // <https://elixir.bootlin.com/linux/v6.18/source/drivers/input/serio/i8042-acpipnpio.h#L1578>.
+            //
+            // Currently, we lack the necessary support, so we allow the user to manually override
+            // the ACPI flag by appending "i8042.exist" to the kernel command line.
+            //
+            // TODO: Add support for enumerating PnP devices and remove the command line option.
+            if !Self::is_present_cmdline() {
+                log::info!(
+                    "ACPI says i8042 controller is absent; \
+                    if it is incorrect, append 'i8042.exist' in cmdline to override it"
+                );
+                return Err(I8042ControllerError::NotPresent);
+            } else {
+                log::info!(
+                    "ACPI says i8042 controller is absent; \
+                    however, it is overridden by 'i8042.exist' in cmdline"
+                );
+            }
+        } else {
+            log::info!("ACPI says i8042 controller is present");
         }
 
         let controller = Self {
@@ -147,6 +165,26 @@ impl I8042Controller {
         Ok(controller)
     }
 
+    fn is_present_acpi() -> bool {
+        ACPI_INFO
+            .get()
+            .unwrap()
+            .boot_flags
+            .is_some_and(|flags| !flags.motherboard_implements_8042())
+    }
+
+    /// Checks if the kernel command line contains the "i8042.exist" option.
+    fn is_present_cmdline() -> bool {
+        !KCMDLINE
+            .get()
+            .unwrap()
+            .get_module_args("i8042")
+            .is_some_and(|args| {
+                args.iter()
+                    .any(|arg| matches!(arg, ModuleArg::Arg(s) if s.as_bytes() == b"exist"))
+            })
+    }
+
     fn read_configuration(&mut self) -> Result<Configuration, I8042ControllerError> {
         self.wait_and_send_command(Command::ReadConfiguration)?;
         self.wait_and_recv_data()

kernel/src/device/tty/device.rs

@@ -6,6 +6,7 @@
 //!
 //! Reference: <https://www.kernel.org/doc/html/latest/admin-guide/devices.html>
 
+use aster_cmdline::KCMDLINE;
 use device_id::{DeviceId, MajorId, MinorId};
 use spin::Once;
 
@@ -22,7 +23,6 @@ use crate::{
         device::{Device, DeviceType},
         inode_handle::FileIo,
     },
-    kcmdline::KCmdlineArg,
     prelude::*,
     process::{JobControl, Terminal},
 };
@@ -104,7 +104,9 @@ impl SystemConsole {
 
         INSTANCE.call_once(|| {
             // TODO: Support specifying multiple TTY devices, e.g., "console=hvc0 console=tty0".
-            let console_name = KCmdlineArg::singleton()
+            let console_name = KCMDLINE
+                .get()
+                .unwrap()
                 .get_console_names()
                 .first()
                 .map(String::as_str)

kernel/src/init.rs

@@ -2,6 +2,7 @@
 
 //! Kernel initialization.
 
+use aster_cmdline::KCMDLINE;
 use component::InitStage;
 use ostd::{
     arch::qemu::{exit_qemu, QemuExitCode},
@@ -12,7 +13,6 @@ use spin::once::Once;
 
 use crate::{
     fs::{fs_resolver::FsResolver, path::MountNamespace},
-    kcmdline::KCmdlineArg,
     prelude::*,
     process::{spawn_init_process, Process},
     sched::SchedPolicy,
@@ -144,7 +144,7 @@ fn first_kthread() {
     print_banner();
 
     INIT_PROCESS.call_once(|| {
-        let karg = KCmdlineArg::singleton();
+        let karg = KCMDLINE.get().unwrap();
         spawn_init_process(
             karg.get_initproc_path().unwrap(),
             karg.get_initproc_argv().to_vec(),

kernel/src/lib.rs

@@ -46,7 +46,6 @@ mod events;
 mod fs;
 mod init;
 mod ipc;
-mod kcmdline;
 mod net;
 mod prelude;
 mod process;